Inductions!
by I'm Nova
Summary: Many fans believe Sherlock uses induction, not deduction in his investigations. I bet you read something of the sort, too. Well, what does he have to say about it? Listed humor mostly for the planned next chapter.
1. Chapter 1

Inductions?!

It has been brought to my attention, by a deeply mortified Watson, that many of his fans believe my reasoning to be not of the deductive, but of the inductive kind. The evidence they bring is my having cleared my brain attic from any philosophy which was drilled into me at school and my use of facts to draw conclusions. As I said to my Boswell, it's not all the fault of his romantic writing style: I suspect these philosopher-wannabes would not understand it anyway. That I would not know what goes through my own brain is, however, a most insulting claim and I find myself forced to disprove it.

I indulge in induction: any scientific work is such an endeavour, therefore my experiments all fall into that category. My investigations, though, allow me to stretch my deductive powers. For anyone who may still be confused about the difference, induction means discovering a general rule by way of seeing it confirmed in as many actual instances as one can gather. It is always at risk of being disproved by an evidence to the contrary.

I said, a long time ago, that my self-developed chemical test will pinpoint blood only, and indeed my experiments proved it is not subject to the shortcomings other widely used similar tests suffer. My statement was, however, much too bold – because of my enthusiasm at the time. I have not tried it on many things, after all (from gold to numerous exotic plants) and I suppose some of them could give a positive result. However no man, even in all his lifetime, would have the chance (and single-mindedness) to develop a test examining every substance in the world. And the chance of a sample's behaviour being abnormal for some reason can never be completely overruled. The best a scientist can say, with the result of his experiments and those of his colleagues, is that the probability of a reaction offering a particular result is, indeed, very high. And sometimes, being proved wrong damages more than just one's pride...but that's not the point.

Deduction, instead, starts from general truths and offers details about one specific instance, and can't be wrong, unless one's premises are erroneous themselves or one treats them illicitly.

The classic example for deductive thinking is the following syllogism:

Major premise – All men are mortals

Minor premise – Socrates is a man

Conclusion – Socrates is mortal.

If any of you are wondering why I even remember this, I may have erased the Greeks' ethics or metaphysics (they're outdated anyway), but thought-process models simply stuck (and at least when I pine for a case I know what I'm yearning for).

I'd like to draw your attention to the minor premise which is, in theabove example, hard fact.

When I offer my explanations to Watson, I leave the general rules implicit: they are obvious, after all, and I'm not prone to stating blatant things. He understands, of course, and does not need it in the open. For the dimwits who can't see it, though, I'll offer you an example:

Major premise: There is a mathematical ratio between the length of one's legs and one's height, as well as between one's footprints' distance and their legs' length (general truth).

Minor premise: The man I'm looking for left footprints whose distance I can measure (data).

Conclusion: My quarry's height is so-and-so (particular instance).

I've done it a million times. Moriarty did (no wonder, since mathematics make ample use of deductive reasoning). Frankly, I doubt the people who thought they could correct me have ever had one deduction flit through their head, no matter how long they studied the philosophers of old.

P.S. Stay tuned for the shocking revelation next chapter...


	2. Chapter 2

A.N. First of all, kudos to Ennui Enigma for betaing (sorry about last chapter, dear!) and thank you so very much to James Birdsong for the flattering review!

"_(...)__his [Holmes'] time is divided between philosophy and agriculture" - Preface to His Last Bow_...now why is that? Watson's pov, this time.

I count myself lucky to have been witness to one curious accident while I was visiting my old friend, Sherlock Holmes, at his Sussex cottage. The post had brought a voluminous letter from Lestrade. Since our relationship had always been work related, and I knew he was retired now (we were in a different century, after all), I wondered what he could want. Out of the envelope came what I thought would be a case file. Holmes was supposedly retired, too, but his was more a lifelong calling than a job: everyone knew and tried anyway, even if (until then) without success. I was surprised when Holmes skimmed the accompanying letter and dropped it as if it scorched his fingers like burning coals. "Of all the outrageous things..." he began, and I picked up the missive, to see for myself what had upset him so. I'm copying it:

_Mr. Holmes,_

_I know you expect a request of consultancy, but this is not. I can't help myself, though... _

_You know (or you don't, I don't think I've mentioned, but you used to know everything anyhow) my eldest son, Herb, has grown up into a philosopher. Where he took the inclination from, I cannot say, certainly not from me, but I've learned it's mad to stifle one's predisposition because you don't like it. So he goes on forever studying (he's found a work at a little university, even) and knows better than talking about it with me. And I know you're annoyed with me already. _

_The point is, he mentioned you a few years ago, saying a contemporary philosopher – I'd think it was an impossibility if not for Herb – decided there was a new line of reasoning or something, and my son thought it was exactly yours. He called it abducting – at least that's what it sounded like – and I replied you had not that in your crimes' list, at least to my knowledge. I've not written to give cold news, though. _

_A few days ago, he was back home again, and he said that man who'd accused you of abducting had thought the matter over a few decades, and come to a conclusion. He's slow on the uptake, for sure (any Yarder could have told him so when he first started), but he doesn't know you, so I think he's justified. Anyway, he's finally realized the pretty thing you used to do is nothing more than guessing. _

_So I asked Herb to give me an article of this fellow, to prove the matter to you. Remember how angrily you protested whenever we even hinted at it? I've enclosed the evidence. Have a pleasant read. _

_Yours (even if you hate me now),_

_G. Lestrade_

I chuckled. Just like Lestrade, I couldn't help myself.

Holmes interrupted his rant (I admit I had tuned him out) to protest, "Not you too, Watson!".

"Come on, old fellow, it's not so bad..." I replied.

"Not bad?" he echoed, clearly indignant.

"Quite well-timed, I'd say. After all, you do need a pastime for the rainy days. But for the violin, your indoor hobbies used to be...hazardous, to say the least," I explained. I still remembered some experiments which ended in small (luckily) fires or an half-asphyxiated sleuth.

"They weren't all that dangerous," Holmes objected.

"Compared to the rest, certainly not, but this bloke needs to be proven wrong anyway, doesn't he? If this...philosopher backpedals, Lestrade, the old and the young both, will have to acknowledge it. If you don't, I doubt anyone else will care to demonstrate to an old academic how stupid he is," I goaded my friend.

"I suppose a response_ is_ in order," he agreed.

"Let me know how it proceeds, will you?" I queried.

"Of course, Watson," Holmes acquiesced "you didn't need to ask".

P.S. A philosopher (who would have been fifteen years Sherlock's senior...if Sherlock were real) named Charles Sanders Peirce added a third genre of reasoning to induction and deduction, Abduction, which is the one Sherlock really utilizes. It is the use of a known rule to explain a result. This kind of inference originates a hypothesis by concluding in an explanation, though an uncertain one (hence it will need confirmation), for some anomalous observation stated in a premise.

One example of abductive hypothesis I found on both Wikipedia and the book I discovered Peirce on, so I think it's a classic:

Rule: All the beans from this bag are white.

Result: These beans [oddly] are white.

Case: These beans are from this bag.

It is weird enough to deserve being used for a casefic, I think...but I have no idea how to do it, so you're welcome to it.

...Around 1900 Peirce decided Abduction could be defined as guessing.

Honestly, the main difference I find with deduction is that abduction is always about something specific (and odd), while deduction can give conclusions about whole categories (and be desperately obvious- check any syllogism example you can find). But no professor explained Peirce to me (I was tricked into buying a book with articles on him by Sherlock's name on the cover), so I may be wrong.


	3. Chapter 3

A.N. Thank you so very much to everyone who liked this fic! This chapter wasn't originally meant to be, but let's hope for the best... As always, send your gratitude to my wonderful beta, Ennui Enigma, who helps to make my work understandable!

Happy Easter to you all!

_My dear Watson, _

_you've asked news about my philosophical endeavours. I have kept you in the dark for months, when I had promised not to; but honestly, I hoped to offer you the announcement of my victory in the dispute. Not only has that not yet happened, but also it looks like I'm facing a challenge which could very well keep me occupied for years to come. _

_That man is insufferably obstinate, Watson! I'm not even sure he deserves to be called a philosopher at all. Weren't philosophers meant to search for the truth? Why does he refute it when it's plainly explained? He's a sophist, if anything. _

_Peirce still insists abduction is 'very little hampered' by rules of logic, 'intuitive', 'oftener wrong than right'. Disgusting. Of course he'd call it a guess. And he still extols it, as the only line of reasoning with creative, almost revolutionary potential. What good could come from it, if his theories were right?_

_When I suggested that, despite having invented the definition, Peirce is clearly not proficient at abducting, and that's what has caused his misinterpretation, he reacted quite hotly. _

_But really, Watson, 'oftener wrong'? Such a statement is evidence enough the man has no idea what he's talking about. You're my companion and my witness: I'm far from perfect, but out of all the times I have applied my methods, I was decidedly 'oftener right'. Not to mention, I would never even have started a career as consultant if I were not. _

_It's no wonder Peirce's success rate is low seeing how he discards logic's rules so airily and his conclusions rest upon intuition, of all things. I even offered to teach him how to reason properly – it surely wouldn't hurt – but he fails to see his own fallacies._

_I told him that with his slander he hinders the widespread usage of abduction in fields that really need it (now that I'm retired, a few more Yarders like Hopkins would be mightily useful), but not even the public good moves him._

_I will continue my efforts to make him see the truth. You know I do not back down easily. I have to confess, though, I find academics more entertaining – and decidedly easier to deal with – when they break the law outright. Will you forgive me such a statement, dear fellow?_

_Hope to see you soon, _

_Sherlock Holmes _

P.S. About the philosopher/sophist difference: In Ancient Greece (V century b. C.) sophists were intellectuals who were paid (handsomely) to teach the art ofdebating to young men who wanted a future in politics. Sophists (Gorgias, Protagoras and others) were famous because, to demonstrate their prowess, they would persuade their public of something and right after they would affirm the contrary – and persuade the selfsame public again. Obviously, truth was not their main concern. Again obviously philosophers (especially Plato) did not like sophists at all. After all, both were in competition for the same pupils.

Probably not what you hoped for...but my book did not explain clearly _why _Peirce claimed Abduction was guessing, and I can't answer to arguments I do not know. So, until I find data on it, I can't make bricks...er, chapters... and this is 'complete'. Of course, if you have said data (or links to them), let me know and I will try to add something. ;-)


End file.
